190 
Proceedings of the Royal Society of Edinburgh. [Sess. 
melted first (a furnace with mechanical blower being used) under charcoal, 
glassy borax was added as a flux, and the aluminium was then gradually 
stirred in by a wooden rod. Two of the products were too brittle to draw, 
but a wire of 15 cms. length and ’5 mm. diameter was got from the third 
casting. This was subsequently analysed in the chemical department and 
gave as constituent proportions, copper 74‘4, aluminium 6'2, and zinc 19’6 
per cent. This wire when oscillated and tested gave the values : 
A. a = l B. a=l 
H=T75 n—l' 55. 
Repeated experiments gave similar values. The wire was then raised 
successively to temperatures of 300° C., 375° C., 400° C., 425° C., 450° C.. 
and 500° C., but after cooling no change in the constants was obtained. A 
steady state as regards change by temperature must then have been reached 
in the heating undergone while the wire was being drawn. 
A series of four copper-aluminium alloys were also cast and drawn in 
